Fabrication and characterization of small-caliber nanofibrous vascular scaffolds with sustained release of endothelial cell derivatives and heparin.

Introduction: Cardiovascular diseases are a leading cause of mortality, and artificial blood vessels as an alternative strategy are extensively used in clinical settings. Due to the underlying potential for thrombus formation and intimal hyperplasia, the clinical applications of small-caliber (<6 mm) artificial vessels are limited. Promoting rapid endothelialization and enhancing anticoagulant ability are pivotal approaches to achieve long-term patency of small-caliber artificial vessels. Methods: Biocompatible PCL-ECd nanofibers with a core-shell structure were prepared using coaxial electrospinning. PCL served as the shell layer providing mechanical support, while 30% ECd formed the core layer, accelerating endothelialization. Additionally, incorporating 10% heparin into the core layer endows the P-E/H nanofibers with the desired anticoagulant properties. Coaxial-emulsion electrospinning enables sustained release of ECd and heparin from P-E/H. Finally, the in vitro patency of 4 mm diameter P-E/H vascular scaffolds was evaluated using a closed-loop system. Results: P-E/H nanofibers exhibited enhanced endothelial cell proliferation, superior hemocompatibility, and ideal anticoagulant properties. The in vitro blood flow patency of a 4 mm diameter P-E/H vascular scaffold indicated the absence of any clot or thrombus. Conclusion: This study proposed a new strategy for developing small-caliber vascular scaffolds with enhanced hemocompatibility and sustained anticoagulant activity.